#include <bits/stdc++.h>
using namespace std;
bool ishui(int num)
{
    if(num<0)
        return false;
    int left = 1;
    while(num/left >= 10)
        left *= 10;
    while(num>0)
    {
        if(num/left!=num%10)
            return false;
        num = num%left/10;
        left/=100;
    }
    return true;
}
int main() {
    int a = 12321;
    ishui(a)?cout<<"是回文":cout<<"不是回文";
    return 0;
}